The twosome attended Primary Wave's 10th Anniversary and Candy Crush Jelly Saga pre-Grammy party Sunday in West Hollywood, and as an eyewitness tells E! News exclusively, they were very lovey-dovey throughout the night!

The One Direction boy-bander was holding her from the back and kissing her cheeks and lips, says the onlooker. Louis, 24, "was very into her and you could tell," says a party-goer. "He kept on making her laugh."

The new dad was a "true, complete gentleman," according to an eyewitness.

When asked if she thought Louis and bandmates Harry Styles, Niall Horan and Liam Payne would all have solo success at some point like former 1D member Zayn Malik, Danielle played it P.C. "Yeah, all of the boys are extremely talented," she told E! News exclusively, "and I know they will be very successful."

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